Vehicle light control



Feb. 18, 1964 E. w. BROCK ETAL 3,121,823

VEHICLE LIGHT CONTROL Filed Sept. 25, 1959 2 Sheets-Sheet 1 AUTOMATIC DIM M ER CONTROL IN VEN T OR? ATIQRNE Y 1964 E. w. BROCK ETAL 3, ,823

VEHICLE LIGHT CONTROL Filed Sept. 25, 1959 2 Sheets-Sheet 2 IN V EN T0R3 621 ewe %@'oa& B Y $596M 0/7/5322? ATTORNEY United States Patent3,121,823 VEHKILE LIGHT CONTROL Eugene W. Brock and George W. Onlksen,Anderson, Ind, assignors to General Motors Corporation, Detroit, Mich, acorporation of Delaware Filed Sept. 25, 1959, Ser. No. 842,265 7 Claims.(Cl. 315-83) This invention relates to vehicle light switching means andmore particularly to switching control means adapted to be connected .toa light controlled multi-filament lamp circuit to provide anintermediate light intensity condition when switching from bright beamto dim beam operation of vehicle headlights. The present inventionfurther relates to switching means that will provide a distinctive beamchanging operation.

The conventional multi-beam headlamps used on highway vehicles provideeither a high intensity high beam or a relatively low intensity dimbeam. When changing from the high beam to the low beam, the suddenchange in light intensity occurs almost instantaneously and the eyes ofthe driver and drivers of oncoming vehicles require a considerablelength of time to adjust to this change. The present invention providesan intermediate condition when changing from high beam to low beamwherein when the low beams are initially energized as when meeting anapproaching vehicle, the upper beams will remain on for a short periodof time at a reduced intensity. This intermediate condition need onlyexist for only a relatively short period of time, for example, one-halfto several seconds to accomplish the desired result. The two stepdimming outlined above is also advantageous to advise the approachingdriver when a vehicle is equipped with automatic light control means forswitching between high and low beam positions.

It is, therefore, an object of the invention to provide switching meansthat will cause the vehicle headlights to be in an intermediate lightcondition for a brief period when switching from high to low beams.

It is a further object to provide a lighting system wherein whenswitching from upper to lower beams, the upper beams are maintained onat a reduced intensity for a short period of time before being turnedoff completely.

It is still a further object to provide a switching means utilizing abimetallic current carrying switch element that will automatically openafter a predetermined time after the switch is closed.

Still another object is to provide a switching mechanism that can easilybe adapted to present lighting installations.

Other objects and advantages will become apparent from the followingspecification, claims, and illustrations which described and illustratea representative form of the invention and in which:

FIG. 1 is a circuit diagram of the control system embodying myinvention;

FIG. 2 is a elevational view of a special switch mechanism utilized inthe invention, the switch elements shown in high beam condition;

FIG. 3 is a partial view similar to FIG. 2 showing the switch elementsimmediately after they have been moved to low beam condition;

FIG. 4 is another partial view similar to FIG. 2 showing the switchelements in their final low beam condition;

FIG. 5 is a sectional view taken on the line 55 of FIG. 2;

FIG. 6 is a partial sectional view taken on the line 6-6;

FIG. 7 is a partial sectional view taken on the line 77 of FIG. 4-;

FIG. 8 is an enlarged sectional view taken on the line- 8-8 of FIG. 5and FIG. 9 is an end view of the switch mechanism taken on the line 99of FIG. 2.

Referring now to the control diagram of FIG. 1, it will be seen that abattery 1 which may be the vehicle battery, provides a source of voltagethrough a manual light switch 2 to the vehicle lighting system. In theillustrated embodiment a four headlamp lighting system is shown withouter lights 3 and 5 having multi-filaments Zia-3b and 5a5brespectively, while the inner headlamps 7 and 9 each have a singlefilament 7a and 9a. During low beam operation, only the low beamfilaments 3b and 5b connected to low beam lead 11 are energized. Duringhigh or bright beam operation the upper beam filaments 3a and 5a of theouter lamps 3 and 5, as well as the bright filaments in the inner lamps7 and 9 are energized. These filaments are all connected to bright beamlead 13. The invention can also be applied to two headlight systemswithout modification.

A special light control switch generally indicated S, and enclosed inthe dashed line box in FIG. 1, acts to control the filaments in thelamps 3, 5, 7, and 9. The switch S includes a relay coil 15 connected atone end to a control lead 17 and at the other end to the electricalground. A resistor 19 connected across the relay coil 15 dissipatescurrent induced in the coil when the coil is dc-energized. The relaycoil when energized, causes movement of a pair of movable switchelements 21 and 23 normally held in the upper position, as viewed inFIGURE 1, by a spring 25. The movable switch elements 21 and 23 arecommonly connected to the battery lead 27. Switch element 21 carries acontact 2% which in the normal upper position of element 21 engages acooperating contact 31 to connect battery voltage from lead 27 to thehigh beam filament lead 13. When moved by the coil 15 to its lowerposition, the contact 29 on element 21 engages a contact 33 to connectbattery voltage from line 27 to the low lead 11.

The second switch element 23 operated simultaneously with element 21,carries a contact 35 which does not engage any cooperating electricalcontact when the element is in its upper position as shown in FIG. 1.When the element 23 is moved down by the coil 15 being energized, thecontact 35 engages a contact 37 to connect battery 1. to the bright beamlead 13 through a fixed resistor 39. Under this condition the voltage onthe upper beam filaments will be lower than normal so that the intensityof the light produced by these filaments will be lower than normal. Byselecting the proper resistance value any degree of intensity can beobtained.

The switch element 23 is of bimetallic construction and has a small butpredetermined internal resistance. When current passes through theelement 23 from the battery 1 contacts 3537, resistor 39, and lead 13 tothe bright beam lead 13, the power dissipated through the resistanceproduces a torque in the direction of the low expanding side of thebimetal. This action will be explained more ilully below in the moredetailed description of the switch mechanism shown in FIGS. 2 to 9. Thebending torque on element 26 will cause the same to bend and the contact35 will then disengage from contact 37 leaving only the low beamfilaments 3b and 5b energized through lead 11, contacts 3329, switchelement 21, and battery lead 27.

While the present invention could be utilized in a manually controlledvehicle lighting system, we have shown the same in an automatic systememploying a photo-electric automatic dimmer control. The automaticdimmer control, generally designated by the box A, may be of anysuitable form but which is preferably of the type which will cause avoltage to be applied to the output lead 40 whenever the automaticdimmer control reacts to the lights of an approaching vehicle and callsfor a switching the vehicle lights from upper beam to lower beam. Anexample of the type of automatic dimmer control that could be utilizedis shown in US. Patent 2,890,386, entitled Automatic Headlamp ControlSystem. Obviously other automatic systems could be utilized. A twoposition manual-automatic switch 41 shown in the automatic position inFIG. 1, connects the automatic dimmer output lead 40 to the switch relaycoil 19 through the lead 17. When the switch 41 is moved to its otherposition or manual low hem position, the relay 15 is connected by meansof the switch 41 and contact 45 directly to the battery voltage lead 27.This acts to cut out operation of the automatic dimmer control andthrough the switching mechanism S, acts to establish and maintain a lowbeam condition.

A second manually operated override switch 47 connects a control lead 49extending from the automatic dimmer control A to a ground lead 51. Withlead 51 grounded the automatic dimmer control A will always beconditioned for bright beam operation regardless of the amount of lightreceived by the photo-electric pickup, not shown, of the automaticdimmer control.

Referring now to FIGS. 2 through 9 which show the details of the switchmechanism S, it will be seen that a relay coil 15 corresponding to coil15 of FIG. 1 is mounted on a switch frame 53. Pivoted on the frame andpositioned immediately above the coil 15, is a lever type armature 55which is biased away from the coil by a spring 25. R-iveted to thearmature 55 is a leaf spring switch element 21 corresponding to e switchelement 21 shown in the circuit diagram FIG. 1.

The spring element 21 has a contact 29 on its free end which normallyengages a contact 31, as shown in FIG. 2. Contact 31 is carried on aflange 59 formed on a plate member 60, in turn fastened to the switchframe 53 by an insulating and mounting plate 62. The member 61 has anextending prong 71 for connection to the upper beam lighting lead.

Located below and in the path of contact 29 is another contact 33attached to a flange formed on a plate member 64. The plate 64 issupported by the insulating plate 62 and has a connector prong 73extending therefrom. The plate 64 and its prong 73 are adapted to beconnected to the lower beam lighting lead 11 of FIG- URE 1.

Also attached to the armature 55 is a bimetallic member 57 having a slot56 formed near the center thereof. Riveted to the bimetallic element 57is a second switch element 23 which is fabricated to have an innerextending tab portion 61 and outer portions 62 which are joined togetheron their ends remote from the attachment point element 57. The remoteend carries a movable contact 35 corresponding to the contact 35 inFIG. 1. An overcenter C spring 63 has slots on each end that engage theinner portion 61 and an insulated tongue 58 attached to the outerportion of the spring 23. The spring 63 normally holds the element 23 inthe shape shown in FIG. 8. The switch element 23 is also of bimetallicconstruction and has a predetermined internal resistance so that currentflowing through the same will cause a torque on the spring member 23 tobend end of the same upward as viewed in FIG. 8 against the force of thespring 63. When the torque due to the bimetallic uneven expansion of themember 23 is sufficient to overcome the force of the overcenter spring63, the outer end of the element 23 will snap into the position shown inFIG. 4.

Located directly below the contact 35 carried by the element 23 is acontact 37 which is carried by a flanged plate member 65 which extendsout and has a connecting prong 77 formed thereon. Formed immediatelyabove contact 35 is a non-conductive reset button 67 carried on a flangeportion 66 of the member 60. This reset button acts to snap the springswitch member 23 into its original shape of FIG. 8 upon release armature55 by the coil 15.

A flexible wire 70 connects the element 57 and thus the two switchmembers 21 and 23 to a plate 72 having a pronged end 75. The prongs 71,73, 75, 77, and 79 are adapted to fit into corresponding sockets (notshown) in a mounting board suitably located in the vehicle. Thesesockets connect to the various battery, automatic dimmer and headlightwires. Prong 71 connects to the upper beam lead 13 of FIG. 1, prong 73to the lower beam lead 11, prong 75 to the battery voltage wire 27 andprong 77 to the voltage reducing resistor 39. One of the prongs 79connects to the automatic dimmer lead 17 and the other to the vehicleelectrical ground.

It should be pointed out that the resistor 39 serves a double purpose.iBtZSldES providing a voltage drop to lower the intensity of the upperbeam filaments, it is of the ceramic fuse resistor type which will blowor burn out in the event of bimetal switch failure in the on or downposition. Thus, the system has a fail safe feature in that upon burnoutof the fuse resistor, the light switch relay will perform as aconventional high-low beam control switch.

The bimetal element 57 acts to compensate the bimetal switch 23 foroperation over :a large ambient temperature range. This element 57 actsto regulate the contact pressure of the bimetal snap switch 23 tocorrect for the ambient temperature effects on the switch itself.Element 57 has a low internal resistance and hence is not affected bycurrent flow through itself. By changing the design of the bimetalswitch element 23, the period that the bright filaments remain onreduced intensity during a bright to dim change can be varied.

Operation The operation of the system will now be described. With theheadlamps turned on by closing switch 2, and switch 41 in its automaticposition shown in FIG. 1, the automatic dimmer contact A will normallybe in bright or upper beam condition and no voltage will appear at lead40. The relay coil 15 will then be deenergized and the switch element 21will be positioned as shown in FIGS. 1, 2, 5, 8, and 9. Battery voltagewill then be applied through lead 27, switch 21, contacts 29-31 to thebright beam lead 13 and through the bright beam filaments 3a, 7a, 9a,and 5a to the electrical ground. The upper section of the switch Sincluding switch member .23 is then in its normal upper position andmakes no electrical connection.

When the automatic dimmer control A responds to the lights of anoncoming vehicle, battery voltage is applied to lead 40 and through theswitch 41 to the relay coil 15. Coil 15 is also energized when switch 41is moved to its manual low beam position. With coil 15 energized, thearmature and switch elements 21 and 23 are pulled down to the positionshown in FIGS. 3 and 6. Contact 29 then engages contact 33 to applybattery voltage from line 27 to the dim or low beam line 11. At the sametime contacts 29-31 are opened disconnecting the original circuit to theupper beam lead 13. Simultaneously a circuit is completed from thebattery 1 through switch member 23, contacts 35-37, and through the fuseresistor 39 to the upper beam line 13. This causes a reduced current toflow through the upper beam filaments, causing the light intensity ofsaid lamps to be reduced to approximately one-half brilliance. Thecombination of lower beam plus reduced upper beam provides a noticeableoverall reduction in light brilliance or glare from the normal brightbeam condition.

Current passing through the bimetal switch member 23 heats the samecausing it to snap away from contact 37 when sufficient torque isobtained to overcome the action of the overcenter spring 63. This can bemade to occur after any period of time, however, a period ofapproximatedly one second has been found to be satisfactory. After thebimetallic switch 23 has snapped the parts are as shown in FIGS. 4 and7. The spring 63 holds switch 23 in the FIGURES 4 and 7 position switch23 cools.

When the automatic dimmer A removes the voltage from lead 40, thearmature and switch elements 21 and 23 are released, contacts 2933disengage and contact 2931 engage to restore the lower beam condition.At the same time the contact 35 engages reset button 67 to cause theswitch 23 to snap back over center to its original position ready forthe next operation.

The invention can be installed in present vehicles without disturbingthe wiring harness and can be utilized in both manual and automaticlighting systems. The use of the invention will provide a greater degreeof safety during night driving. Changes and modifications will beapparent to those skilled in the art as will other applications of theinvention. These changes and applications are within the scope of theinvention which is limited only by the following claims.

We claim:

1. In a vehicle lighting system having upper and lower beam lightingfilaments, switching means for changing from full intensity upper beamoperation to lower beam operation, and means for continuing operation ofthe upper beam filaments at a reduced intensity for a predeterminedperiod after said lower beam filaments are energized for full intensityoperation.

2. In a vehicle lighting system having upper and lower beam lightingfilaments, a voltage source, switching means for alternativelyconnecting said upper beam and lower beam filaments to said voltagesource, and means including an electrical resistor providing a secondconnection between said upper beam filament and said voltage source whensaid switching means connects said lower beam filament to said voltagesource, said last mentioned means including a delayed action switch foropening said second connection after a predetermined period of time.

3. In a vehicle lighting system having bright and dim filaments, thecombination including, a voltage source, first switch means foralternatively connecting said voltage source to said filaments fornormal operation thereof, and second switch means for establishing asecond connection between said bright filament and said voltage sourcethrough a voltage dropping resistance to provide reduced intensityoperation of said bright filaments, common means for actuating saidfirst and second switch means to change from bright filament onlyoperation to operation of both bright and dim filaments with said brightfilament operating at a reduced intensity, said sec ond switch meansincluding heat responsive means for opening said second connectionbetween said bright filament and said voltage source through saidresistance a predetermined time after said second connection has beenmade.

4. In a vehicle lighting system having bright and dim filaments, thecombination including, a voltage source, first switch means foralternatively connecting said voltage source to said bright or dimfilaments for normal operation thereof, second switch means forestablishing a second connection between said bright filament and saidvoltage source through a voltage dropping resistance to provide reducedintensity operation of said bright filament, and common means foractuating said first and second switch means to change from brightfilament only operation to operation of both bright and dim filamentswith said bright filament operating at a reduced intensity, said secondswitch means including bimetallic current responsive means for openingsaid second connection between said bright filament and said voltagesource through said resistance a predetermined time after said secondConnection has been made.

5. In a vehicle lighting system having bright and dim filaments, thecombination including, a voltage source, first switch means foralternatively connecting said voltage source to said bright or dimfilaments for normal operation thereof, second switch means forconnecting said bright filament to said voltage source through a voltagedropping resistance to provide reduced intensity operation of saidbright filaments, means for concurrently actuating said first and secondswitch means to change from bright filament only operation tosimultaneous operation of both bright and dim filaments with said brightfilament operating at a reduced intensity, said second switch meansincluding snap action bimetallic current responsive means for openingsaid connection between said bright filament and said voltage sourcethrough said resistance a predetermined time after said connection hasbeen made by said second switch means, and ambient temperture responsivemeans connected to said snap action means to provide for constant timedelay at different ambient temperatures.

6. In a vehicle lighting system having bright and dim filaments, thecombination including, a voltage source, first switch means foralternatively connecting said voltage source to said bright or dimfilaments for normal operation thereof, second switch means forestablishing a second connection between said bright filament and saidvoltage source through a voltage dropping resistance to provide reducedintensity operation of said bright filament, common means for actuatingsaid first and second switch means to change from bright filament onlyoperation to operation of both bright and dim filaments with said brightfilament operating at a reduced intensity, said second switch meansincluding heat responsive means for opening said connection between saidbright filament and said voltage source through said resistance apredetermined time after said connection has been made and means forholding said second connection open until said common actuating meansreleases said first and second switch means.

7. In a vehicle lighting system having bright and dim filaments, thecombination including, a voltage source, first switch means foralternatively connecting said volt age source to said filaments fornormal intensity operation thereof, second switch means for establishinga second connection between said bright filament and said voltage sourcethrough a voltage dropping resistance to provide reduced intensityoperation of said bright filament, coil means for operating said firstand second switch means to change from bright filament only operation tooperation of both bright and dim filaments with said bright filamentoperating at a reduced intensity, said second switch means includingbimetallic current responsive means for opening said second connectionbetween said right filament and said voltage source through saidresistance a predetermined time after said second connection has beenmade, automatic light responsive means, and third switch means operableto connect said coil means to said automatic light responsive means orto said voltage source.

References Cited in the file of this patent UNITED STATES PATENTS1,917,532 Loewenstein July 11, 1933 2,700,709 Byam Ian. 25, 19552,700,710 Glickma-n et a1 I an. 25, 1955 2,786,963 Vogt Mar. 26, 195.72,884,564 McIlvaine Apr. 28, 1959 2,917,665 Carpenter et al Dec. 15,1959 2,918,604 Johnston Dec. 22, 1959

5. IN A VEHICLE LIGHTING SYSTEM HAVING BRIGHT AND DIM FILAMENTS, THECOMBINATION INCLUDING, A VOLTAGE SOURCE, FIRST SWITCH MEANS FORALTERNATIVELY CONNECTING SAID VOLTAGE SOURCE TO SAID BRIGHT OR DIMFILAMENTS FOR NORMAL OPERATION THEREOF, SECOND SWITCH MEANS FORCONNECTING SAID BRIGHT FILAMENT TO SAID VOLTAGE SOURCE THROUGH A VOLTAGEDROPPING RESISTANCE TO PROVIDE REDUCED INTENSITY OPERATION OF SAIDBRIGHT FILAMENTS, MEANS FOR CONCURRENTLY ACTUATING SAID FIRST AND SECONDSWITCH MEANS TO CHANGE FROM BRIGHT FILAMENT ONLY OPERATION TOSIMULTANEOUS OPERATION OF BOTH BRIGHT AND DIM FILAMENTS WITH SAID BRIGHTFILAMENT OPERATING AT A REDUCED INTENSITY, SAID SECOND SWITCH MEANSINCLUDING SNAP ACTION BIMETALLIC CURRENT RESPONSIVE MEANS FOR OPENINGSAID CONNECTION BETWEEN SAID BRIGHT FILAMENT AND SAID VOLTAGE SOURCETHROUGH SAID RESISTANCE A PREDETERMINED TIME AFTER SAID CONNECTION HASBEEN MADE BY SAID SECOND SWITCH MEANS, AND AMBIENT TEMPERTURE RESPONSIVEMEANS CONNECTED TO SAID SNAP ACTION MEANS TO PROVIDE FOR CONSTANT TIMEDELAY AT DIFFERENT AMBIENT TEMPERATURES.